June 30 — Hurricane Katrina, the most deadly and destructive storm to hit the United States, caused 1800 deaths and an estimated $81 billion in damages. Most of the loss was not due to the storm’s high winds, but the accompanying storm surge and flooding.
Imminent climate change and sea level rise could possibly make these mega storms more frequent and intense, and especially disastrous to those living on the coast. While it’s challenging, beginning to quantify future loss from storms may help communities start planning to prevent unnecessary death and destruction.
Francisco Olivera, associate professor of Civil Engineering at Texas A&M University, is evaluating the impact of hurricanes and coastal flooding on the Gulf Coast. His group’s assessment of the damage caused by current and future hurricane storm surges has been published in the Journal of Geophysical Research: Oceans, the Journal of the American Water Resources Association, Climatic Change, and Ocean and Coastal Management. These studies represented the first of their kind to explore how the coastlines would change from rising seas.
With funding from the Texas Sea Grant, results from the study are being used to quantify the total damage that Corpus Christi, Texas; Gulf Port, Mississippi; and Panama City, Florida, will face from future storms.
Using data from the national hurricane database, the researchers first modeled five hurricane parameters including central pressure deficit, radium of maximum wind, forward velocity, angle of approach, and landfall location on the program ADCIRC. Once modeled, the researchers were able to determine the storm surge and resulting water levels on the coastline.
“After we identified the water levels along the coastline from the hurricane, we then identified each building impacted by flooding and could calculate its damage,” Olivera said. “This is something that takes a lot of time if you do it on a regular computer. On top of that, we cannot easily think about one hurricane — hurricanes are part of a population of hurricanes. We had to represent the damage of half a million hurricanes for each property in each city we were evaluating.”
The Texas Advanced Computing Center (TACC) provides the computing power needed to accurately estimate this damage.
In 2010, Olivera and his team began using the TACC resources Ranger and Lonestar, through the Extreme Science and Engineering Discovery Environment (XSEDE), a single virtual system funded by the National Science Foundation (NSF) that allows scientists to interactively share computing resources, data and expertise. They now use Stampede, one of the world’s most powerful supercomputers that can perform nearly 10 quadrillion math operations per second.
“Our research has been tremendously impacted by TACC ,” said Celso Ferreira, a researcher on Olivera’s team. “We are highly dependent on TACC resources to perform most of our research projects.”
Supercomputing helps the team consider climate change, an important factor in assessing hurricanes for 50 and 100-year periods. However, there is uncertainty among scholars about how climate change will impact hurricane strength, frequency, and sea level rise. That is why the researchers run simulations for optimistic, pessimistic, and middle of the road scenarios of hurricane storm surge based on climate change. The simulations allow them to calculate the possible percent damage for the different scenarios.
The researchers work under the assumption that as the temperature rises, ice will melt and the ocean will rise, and that will intensify the damage from hurricane storm surge.
“Just picture a relatively flat beach and a house you built 10 or 20 years ago,” Olivera said. “Now in 50 years, the sea level is going to rise which will move the shore inland. What was safe five years ago, is going be right on the edge by 2050, so that means your house will get flooded very frequently.”
Hurricane models, estimated inundation levels, and climate change are all used to calculate risk, the overall expected annual loss measured in terms of dollars. However, the total cost in damages is not always the best indicator of devastation. Olivera and his team also look at the socioeconomic status of the area to truly gauge loss.
Said Olivera: “Katrina flooded a specific area of New Orleans and it was a disaster — many people lost their homes. If you added the value of all those houses, and compared it to a much smaller flooding in a more affluent neighborhood, the monetary value would be similar. But those people most likely have insurance, a well-paying job, and can bounce back in two days, while the consequences of Katrina are still being felt today.”
To help communities begin planning for impending storms, Olivera is part of the Resilience and Climate Change Comparative Project (RCCP), a transdisciplinary team of climate scientists, civil engineers, and urban planners. The team is working with communities and their leaders on the Texas coast to determine the future landscape of development.
According to Olivera, this is a lifelong project.
“Greater collaboration with urban planners is on the horizon for our group. From the technical point of view, we have a good approach to calculating the damage and identifying flooded areas, but we need to use our resources better. And us engineers are not going to do it alone, it’s time to go beyond the boundaries of our own field.”
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Source: Makeda Easter, Texas Advanced Computing Center